1. Field of the Invention
The present invention relates to a handle for motorcycles that has a vibration proof function.
2. Description of Related Art
A conventional vehicle handle with a vibration proof function is disclosed in JP-UM-A-60-34978, and illustrated in FIG. 10. Vehicle handle 100 comprises a handle pipe 101 having a hollow interior, a balance weight 102 arranged in the handle pipe 101, a screw rod portion 103 fixed at one end to the balance weight 102, a floating damper 104 interposed between the other end of the screw rod portion 103 and an inner surface of the handle pipe 101, a nut 105 threaded onto the screw rod portion 103, and a support piece 106 fixed to the nut 105 to support the screw rod portion 103 on the handle pipe 101. G denotes a center-of-mass position of the balance weight 102.
When vibrations from an engine, etc. are transmitted to the vehicle handle 100, the balance weight 102 rocks and vibrates about the support piece 106 against the elasticity of the floating damper 104. Vibrations of the handle 100 can be decreased by that damping action, which makes use of resonant vibrations of the balance weight 102. That is, resonant vibrations of the balance weight 102 are matched with and absorb resonant vibrations of the vehicle handle 100.
However, vibrations of the balance weight 102 consist of rocking vibrations and present frequency characteristics having a single resonance frequency as indicated by an alternate long and short dash line in FIG. 5, and damping is possible only in a band around this single resonance frequency.